Re: OS !== UX && OS !== CPU
I am afraid that in this case, the convergence of the OS also means a convergence of the UX. In particular, I'm afraid that because most Mac users use it for very little serious work, the UX is going to converge to a consumer experience similar to the phones.
There has already been a few changes in that direction. For instance, they had in Finder windows this "All my files" folder, which is so useless to anybody doing serious work on a computer that's it's almost insulting. I think that's been removed now (and of course you have people complaining since it was so useful to them), but it's a pretty good indication of what can go wrong when you design for your average users.
A bit like when Windows introduced the ribbon, and the most prominent buttons were "copy" and "paste".